[PATCH v2 0/4] Make IA32_EMULATION boot time overridable

[Nikolay Borisov <nik.borisov@suse.com>]

Here's the 2nd version of the patch which aims to make IA32_EMULATION essentially
a boot time option. The changes in this posting are:

* Introduced a compile-time option CONFIG_IA32_EMULATION_DEFAULT_DISABLED which
can be set during compile time and can be overriden at boot time via a new
parameter 'ia32_mode'.

* Documented the new parameter as per Thomas' suggestion

* Added a new patch which renames ignore_sysret as per Andrew Cooper's suggestion

* Fixed compat_elf_check_arch condition check to only affect compat process
loading and leave x32 abi processes alone

* Dropped GDT modification as this was deemed a separate change. Likely I'd need
to follow up with a more complete solution.

Nikolay Borisov (4):
  x86: Introduce CONFIG_IA32_EMULATION_DEFAULT_DISABLED Kconfig option
  x86/entry: Rename ignore_sysret and compile it unconditionally
  x86/entry: Disable IA32 syscall if ia32_disabled is true
  x86: Disable laoding 32bit processes if ia32_disabled is true

 .../admin-guide/kernel-parameters.txt         |  4 ++
 arch/x86/Kconfig                              |  5 +++
 arch/x86/entry/common.c                       | 16 ++++++++
 arch/x86/entry/entry_64.S                     |  6 +--
 arch/x86/include/asm/desc.h                   |  1 +
 arch/x86/include/asm/elf.h                    |  9 ++++-
 arch/x86/include/asm/processor.h              |  2 +-
 arch/x86/include/asm/traps.h                  |  4 ++
 arch/x86/kernel/cpu/common.c                  | 37 ++++++++++---------
 arch/x86/kernel/idt.c                         |  7 ++++
 10 files changed, 67 insertions(+), 24 deletions(-)

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2.34.1